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Mr. Wang and Mr. Li started from school at the same time and walked 5km to a certain place. Mr. Wang walked 1km more every hour than Mr. Li, and finally arrived 10 minutes earlier than Mr. Li, Suppose Mr. Li walks XKM per hour,
Then Mr. Wang's speed is x + 1
5/x-5/(x+1)=1/6
A rural primary school, a, B, C, three teachers teaching language evaluation, mathematics, morality, sports, music, art six courses, each teach two
Judge which two courses they teach according to the following conditions
(1) A like to swim with PE teacher and math teacher
(2) B and music teachers, Chinese teachers like to play football
(3) The PE teacher is older than the Chinese teacher
(4) B is not a PE teacher
(5) Moral teachers and math teachers like to play chess
From (1) (4) because a and B are not PE teachers, so C is PE teacher
From (1) we know that B is a math teacher
A is a Chinese teacher from (2) (3)
So C is a music teacher
From (5) we know that a is a moral teacher
So B is an art teacher
It's better to write a gift to the teachers of Chinese, mathematics, English, science, art and music to reflect the characteristics of the subjects they teach
Must be able to reflect the characteristics of the subject teachers teach!
1. Be able to speak two languages; cultivate a new generation. 2. How can the measuring cup and measuring cylinder inspire the teacher's affection; 3. Exponential function, logarithmic function, trigonometric function, counting with hardship; plane straight line crossing straight line, different plane straight line, line meaning is true. 4
If there are two natural numbers whose greatest common divisor is 4 and the least common multiple is 120, then such a natural array has ()
A. Group 1 B. group 2 C. group 3 d. group 4
4 = 2 × 2120 = 2 × 2 × 2 × 3 × 5, such natural numbers can be 4 and 120, 8 and 60, 12 and 40, 20 and 24
It is known that the opposite number of a is 2 and 1 / 2, and the reciprocal of B is - 1 and 2 / 3. Find the value of a-3b of algebraic formula a + 2B
The opposite number of a is 2 and 1 / 2, that is - 5 / 2, so a = 5 / 2
The reciprocal of B is - 1 and 2 / 3, that is - 5 / 3, so B = - 3 / 5
So (a-3b) / (a + 2b)
=1+（-5b）/（a+2b）
=1+（-5）*（-3/5）/（5/2-2*3/5）
=1+3/(5/2-6/5)
=4 and 9 / 10
If a / B is a rational number, define a new operation "#": a # - B = 2ab-1, for example: (- 3) # - 4 = 2 * (- 3) * 4-1 = - 25, try to calculate: (1) 3 # - 5
If a / B is a rational number, a new operation "#" is defined
A × B = 2ab-1, for example: (- 3) × 4 = 2 * (- 3) * 4-1 = - 25
Trial calculation:
（1）3#（-5）； （2）【3#（-5）】#（-2）
3#（-5）=2*3*(-5)-1=-31
（2）【3#（-5）】#（-2）
=-31#(-2)
=2*(-31)*(-2)-1
=123
There are 48 apple trees and pear trees in the orchard. The number of apple trees is 15 times that of pear trees. How many pear trees are there? (solved by equation)
Suppose there are x pear trees. From the equation of number of pear trees + number of apple trees = 48, x + 15x = 48 & nbsp; 65x = 48 & nbsp; & nbsp; & nbsp; X = 40. A: there are 40 pear trees
Given A-B = 3, B + C = - 5, then the value of the algebraic expression ac-bc-b & # 178; + AB is
-15
ac-bc-b2+ab
=(a-b)c-b(b-a)
=(a-b)c+b(a-b)
=(a-b)(b+c)
=3*(-5)
=-15
A and B supermarkets sell the same kind of beverage. In order to promote sales, they use different preferential ways. If you want to buy this kind of beverage, which supermarket is the best choice?
Supermarket a: supermarket B:
Big bottle small bottle big bottle small bottle
Original price 15 yuan original price 3 yuan original price 15 yuan original price 3 yuan
Sell at a 20% discount, buy a big one and get a small one free
emergency
A supermarket pays off, you buy a big one and a small one. A 14.4, B 15, so a and B count
Given | X-2 | + (2x-3y-1) & sup2; = 0, find the value of the algebraic formula 3x - [(x + y) - (X-Y)]
1. The simplified algebraic formula: 3x - [(x + y) - (X-Y)] = 3x - (x + Y-X + y) = 3x-x-y + X-Y = 3x-2y
2. Because | X-2 | + (2x-3y-1) = 0, so | X-2 | = 0, 2x-3y-1 = 0, so x = 2, y = 1
3. Algebra: 3 * 2-2 * 1 = 6-2 = 4
The value is 4
I hope you can choose the best
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